Here are some quotes from experts who know more about these deranged people than I do.
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People want to be happy and to avoid pain and suffering. They seek to maintain and increase their control over themselves and their surroundings. And they desire to maintain and increase their prestige, respect, and esteem. Viewed from the perspective of these three principles about the self, masochism is a startling paradox.
The self is developed to avoid pain, but masochists seek pain. The self strives for control, but masochists seek to relinquish control. The self aims to maximize its esteem, but masochists deliberately seek out humiliation.
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Krafft-Ebing, the nineteenth-century psychiatrist who coined the term:
"By masochism I understand a particular perversion of the psychical sexual life in which the individual affected, in sexual feeling and thought, is controlled by the idea of being completely and unconditionally subject to the will of a person of the opposite sex; of being treated by this person as a master -- humiliated and abused. This idea is colored by lustful feeling; the masochist lives in fantasies, in which he creates situations of this kind and often attempts to realize them. By this perversion his sexual instinct is often made more or less insensible to the normal charms of the opposite sex - incapable of a normal sexual life - psychically impotent."
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My research, however, did not jibe with my clinical reality. The people who presented to me were not immature or inferior. In fact, the reverse seemed to be the case. Masochists are more likely to be successful by social standards: professionally, sexually, emotionally, culturally, in marriages or out. They are frequently individuals of inner strength of character, possessed of strong coping skills with an ethical sense of individual responsibility. A famous study of the "sexual profile of men in power" found to the researchers' surprise, a high quantity of masochistic sexual activity among successful politicians, judges and other important and influential men..
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http://www.revisef65.org/hayden2.html